As is known, it is convenient to allow customers who enter a shop or shopping center to pick up, handle or try goods before purchase.
This often contrasts with the need to prevent ill-intentioned individuals from taking the goods from the shop or display space.
In order to try to obviate this drawback, anti-theft tags have already been proposed, but they can be used only in enclosed spaces or at least in spaces in which potential buyers are forced to pass, when they exit, through a device for detecting such tags.
It is evident that these devices, besides being often bulky, provide no assurance against theft in open-air exhibitions or if the displays are installed in halls or common areas within shopping centers.
In order to overcome this problem, WO 02/090693 A1 by the same Applicant relates to an anti-theft device constituted by at least one cable (which can be wound and unwound on and from a spool), which is associated, at its free end, with means for detachable engagement with an item to be restrained, said means being adapted to open and close an electrical contact, a control unit being provided which is designed to act in response to the opening/closure of the electrical contact.
It is evident that an anti-theft device of the type described above allows to fasten items to be restrained (such as for example eyeglasses) to displays in a practical and effective way.
However, these kinds of anti-theft devices, by having to use removable engagement means associated with means for opening/closing an electrical contact, have a production cost which makes them inconvenient to use in certain applications.